There are various types of penile prostheses that may be implanted in the corpus cavernosa of the penis to treat erectile dysfunction. Two common types of penile prostheses are non-inflatable, semi-rigid and malleable prostheses, and inflatable prostheses.
The corpus cavernosa is surrounded by a sheath known as the tunica albuginea (hereinafter “tunica”). The tunica is a fairly non-compliant membrane that limits the expansion of the corpus cavernosa. Thus, the tunica limits the size of the semi-rigid penile prosthesis that can be implanted in the corpus cavernosa as well as the amount an inflatable penile prostheses can be expanded within the corpus cavernosa. As a result, the overall size of the erect penis is limited by the tunica.
Peyronie's disease is a disfiguring condition of the penis caused by scarring of the tunica. The scarred tunica causes curvature of the erect penis.